• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.5
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• pp.31-36
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• 2015

As one of the most promising propulsive systems in the future, the dual-mode scramjet engine has drawn the attention of many researches. Detailed flow features concerned with the isolator play an important role in the dual-mode scramjet system. The 2D numerical method has been used for the dual-mode scramjet with wind tunnel. To validate the ability of the numerical model, numerical results have been compared with the experimental results. Overall pressure distributions show quite good match with the experimental results. Back pressure has been studied for maximum pressure rising. According to the results, pressure distribution of supersonic inlet section is not influenced by back pressure. The shock train is pushed towards upstream as the back pressure increases. The maximum value of back pressure without inlet unstart goes up rapidly and then keeps constant when the isolator length increases. The optimal length of isolator section ($L/H_{th}$) is 8.7 in this model.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.4
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• pp.383-390
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• 2010

In this study, a thermoelectric power generation system was constructed for a waste-heat recovery. Thermoelectric modules were attached to a stainless steel duct, and a hot air blower was set such that it faced the duct inlet. We found that to achieve the maximum power out of the system, the temperature in the hot side of the thermoelectric module should be uniform. The optimum compressive pressure exerted on the module was observed. Further, the thermoelectric power performance was evaluated using the heat sink attached to the cold side of the thermoelectric module. In particular, when using a natural-convection heat sink, the power output difference is approximately five times.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.3
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• pp.183-193
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• 2007

Analytic solutions are derived for wave scattering by a semi-infinite breakwater or a breakwater gap with partially reflective front and fully reflective back. The water depth is constant and a regular wave train is normally incident to the breakwater. Wave scattering is studied based on the linear potential wave theory. The governing equation is transformed into ordinary differential equation by using the method of variation of parameters and coordinate transformation. Comparison with finite element numerical solution shows that the analytic solution obtained in this paper gives quite good results. Using the analytic solution, the tranquility of harbor entrance is investigated by changing the reflection coefficient at the breakwater.

• Animal Systematics, Evolution and Diversity
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• v.20 no.1
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• pp.79-85
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• 2004

Pholcus gosuensis sp. novo is described from the entrance zone of Gosu cave, Chungchengbuk-do, Korea. The species is characterized by male palpal organs with three expanded apophyses and developed callosity on procursus, two frontal apophyses of chelicerae and degrading appendix, and sclerotized arches on uterus externus. The species is related to P. crassus Paik 1978 and P. acutulus Paik, 1978 in having identical uncus and embolus but differentiated from those species by the combined characters of large apophyses and heavily sclerotized callosity on procursus, and structure of arches on uterus externus.

• Journal of Chest Surgery
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• v.36 no.6
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• pp.422-426
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• 2003

Primary cardiac tumor has very low incidence, especially in cases of malignancy. A 29 year old male patient visited our cardiologic clinic for recent aggrevation of dyspnea on exertion and palpitation. Echocardiography showed a large tumor in the left atrium, which suggested the left atrial myxoma. Urgent open heart surgery was taken. The operative finding was fossa ovalis based a large tumor (35$\times$90$\times$50 mm) that invaded the posterior wall of LA and right superior pulmonary vein directly. The tumor was excised well by simple dissection, and the final pathologic report was malignant myxofibrosarcoma. His postoperative course was smooth and he was discharged in good health. Postoperative radiation and chemotherapy had taken with satisfactory clinical outcome.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.2
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• pp.101-108
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• 1985

The sea water exchange of Koje Bay in the southeastern part of the Korean Peninsula was estimated on the basis of current measurements and oceanographic observation. The exchange ratio was estimated by salinity differences and tidal prism method. The range of exchange ratio at the central part at the entrance of the bay is estimated to be around $26\%$ at spring tide and 5 to $15\%$ at neap tide. The magnitude of exchange ratio, however, can be changed due to water exchange, hydrometeorological and geomorphological conditions. The flushing time deduced by tidal prism was about 48 hours at spring tide and 81 hours at neap tide. Tidal induced eddy motion may play an important role on the seawater exchange in the bay.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.6
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• pp.371-376
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• 2017

The effect of vortex finder confiqurations on the PM-10 collection efficiencies has been investigated using 7 different types of cyclones. Cyclone inlet velocities were calculated by computational fluid dynamics analysis and PM-10 collection efficiencies were measured from experimental apparatus. The inlet velocities of normal, P and A type cyclones were calculated 15.48 m/sec, 16.03 m/sec and 15.9 m/sec, respectively while experimental results show that PM-10 collection efficiencies were increased 4% for P type and 7% for A type cyclones compared to normal cyclone. Also it was found that there exist optimum parallel head lengths for both P and A type cyclones to maximize the PM-10 collection efficiencies.

• Journal of the Speleological Society of Korea
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• no.67
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• pp.11-20
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• 2005

The envirronment of Gosu cave and distribution of inhabitant were surveyed every month from 2002, April to 2003, march. in Gosu Cave, average temperature in summer was $16^{circ}C$ and in winter $14^{circ}C$. Average humidity in summer was $85\%$ and in winter $90\%$. At the entranceof cave in the site 1, trogloxenes:4 species were observed. Troglophiles: Diestrammena japanica was a large population. inside of cave in the site 2 and in the middle Part of the site 3, troglobites:4 species, troglophiles:2 species, trogoxenes: Rhinoiophus ferrumeqinum korai, skleroprotopus laticoxalis longus were observed. Galloisiana sp. were observed on the ground of the Sindong in the site 4, Pseudocrangonyx asiaticus were obserued in the water of yongsu valley. Troglobites have to be preserve as cave animals living in the darkness for a long time.

• Korean Journal of Plant Taxonomy
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• v.35 no.4
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• pp.287-294
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• 2005

Three unrecorded fern species from the flora of Korea, Nephrolepis cordifolia, Athyrium epirhachis, and Asplenium castaneo-viride, are reported here. Nephrolepis cordifolia, recognized as introduced species and cultivation in Korea until now, is found in the wild at the entrance of small cave in Jeju island. Athyrium epirhachis is found under the Quercus acuta forest at about 400 - 500 m alt. in Jeju island. This species is similar to A. otophorum but different from the latter by having once pinnately divided leaf blade and the decurrent base of ultimate segment. Asplenium castaneo-viride is hybrid between A. ruprechtii and A. incisum and is distinguished from parental species by presence of proliferation, shape of leaf blade, pattern of venation, and leaf texture.

• Explosives and Blasting
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• v.38 no.4
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• pp.37-45
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• 2020

Todo was an uninhabited island located in the sea of Pusan Newport. It was a small island with the height of 32 m above sea level, and its area including the submerged part was approximately 24,400 ㎡. Unfortunately, the island was located exactly in the middle of the narrow entrance way to the North and South Container Wharfs of Pusan Newport so that a number of ships had to turn quickly to avoid collision with the island, which frequently caused collisions with other ships or cranes. To avoid such a danger and make the water way wider and deeper, the Ministry of Oceans and Fisheries decided to remove the island. This was believed to make even super-large vessels operate safely in the sea of Pusan Newport so that the competitiveness of the port could be highly enhanced. This paper describes in detail the whole process of the removing work, which was the first case of successful underwater blasting operation using bulk emulsion explosives and non-electric detonators to remove a whole island in South Korea.